package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import cn.hutool.json.JSONObject;
import cn.hutool.json.JSONUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.entity.Shop;
import com.hmdp.mapper.ShopMapper;
import com.hmdp.service.IShopService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.CacheClient;
import com.hmdp.utils.RedisData;
import com.hmdp.utils.SystemConstants;
import org.springframework.data.geo.Distance;
import org.springframework.data.geo.GeoResult;
import org.springframework.data.geo.GeoResults;
import org.springframework.data.geo.Metrics;
import org.springframework.data.redis.connection.RedisGeoCommands;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.domain.geo.GeoReference;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.Resource;

import java.time.Duration;
import java.time.LocalDateTime;
import java.util.*;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

import static com.hmdp.utils.RedisConstants.*;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class ShopServiceImpl extends ServiceImpl<ShopMapper, Shop> implements IShopService {

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private CacheClient cacheClient;

    @Override
    public Result queryShopByType(Integer typeId, Integer current, Double x, Double y) {
        if(x == null || y == null) {
            Page<Shop> page = query()
                    .eq("type_id", typeId)
                    .page(new Page<>(current, SystemConstants.DEFAULT_PAGE_SIZE));
            return Result.ok(page.getRecords());
        }
        int from = (current - 1) * SystemConstants.DEFAULT_PAGE_SIZE;
        int end = current * SystemConstants.DEFAULT_PAGE_SIZE;
        String key = SHOP_GEO_KEY + typeId;
        GeoResults<RedisGeoCommands.GeoLocation<String>> results = stringRedisTemplate.opsForGeo()
                .search(
                        key,
                        GeoReference.fromCoordinate(x, y),
                        new Distance(5000),
                        RedisGeoCommands.GeoSearchCommandArgs.newGeoSearchArgs().includeDistance().limit(end)
                );
        if(results == null) {
            return Result.ok(Collections.emptyList());
        }
        List<GeoResult<RedisGeoCommands.GeoLocation<String>>> list = results.getContent();
        if (list.size() <= from) {
            return Result.ok(Collections.emptyList());
        }
        List<Long> ids = new ArrayList<>(list.size());
        Map<String, Distance> distanceMap = new HashMap<>(list.size());
        list.stream().skip(from).forEach(result ->{
            String shopIdStr = result.getContent().getName();
            ids.add(Long.valueOf(shopIdStr));
            Distance distance = result.getDistance();
            distanceMap.put(shopIdStr, distance);
        });
        String idStr = StrUtil.join(",", ids);
        List<Shop> shops = query().in("id", ids).last("ORDER BY FIELD(id," + StrUtil.join(",", idStr) + ")").list();
        shops.stream().forEach(shop -> shop.setDistance(distanceMap.get(shop.getId().toString()).getValue()));
        return Result.ok(shops);
    }

    @Override
    @Transactional
    public Result updateShop(Shop shop) {
        if (shop.getId() == null) {
            return Result.fail("店铺id不能为空");
        }
        updateById(shop);
        stringRedisTemplate.delete(CACHE_SHOP_KEY + shop.getId());
        return Result.ok();
    }

    @Override
    public Result queryById(Long id) {
//        缓存穿透
//        Shop shop = queryWithPassThrough2(id);
//        互斥锁解决缓存击穿
//        Shop shop = queryWithMutex(id);
//        逻辑过期解决缓存击穿
        Shop shop = cacheClient.queryWithLogicalExpire(CACHE_SHOP_KEY, id, Shop.class, this::getById, CACHE_SHOP_TTL, TimeUnit.MINUTES);


        if (shop == null){
            return Result.fail("店铺不存在");
        }
        return Result.ok(shop);
    }
    private boolean tryLock(String key) {
        Boolean flag = stringRedisTemplate.opsForValue().setIfAbsent(key, "1",10, TimeUnit.SECONDS);
        return BooleanUtil.isTrue(flag);
    }
    private void unLock(String key) {
        stringRedisTemplate.delete(key);
    }

    public void saveShop2Redis(Long id,Long expireSeconds) throws InterruptedException {
        Shop shop = getById(id);
        Thread.sleep(200);
        RedisData redisData = new RedisData();
        redisData.setData(shop);
        redisData.setExpireTime(LocalDateTime.now().plus(Duration.ofMinutes(expireSeconds)));
        stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY + id, JSONUtil.toJsonStr(redisData));
    }

    public Shop queryWithPassThrough1(Long id) {
        String shopJson = stringRedisTemplate.opsForValue().get(CACHE_SHOP_KEY + id);
        if (StrUtil.isNotBlank(shopJson)) {
            return  BeanUtil.toBean(shopJson, Shop.class);
        }
        if (shopJson != null){
            return null;
        }
        Shop shop = getById(id);
        if (shop == null) {
            stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY + id, "", CACHE_NULL_TTL, TimeUnit.MINUTES);
            return null;
        }
        stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY + id, JSONUtil.toJsonStr(shop), CACHE_SHOP_TTL, TimeUnit.MINUTES);
        return shop;
    }
    public Shop queryWithPassThrough2(Long id) {
        Shop shop = cacheClient.queryWithPassThrough(CACHE_SHOP_KEY, id, Shop.class,
                this::getById, CACHE_SHOP_TTL, TimeUnit.SECONDS);
        return shop;
    }




    public Shop queryWithMutex(Long id) {
        String shopJson = stringRedisTemplate.opsForValue().get(CACHE_SHOP_KEY + id);
        if (StrUtil.isNotBlank(shopJson)) {
            return  BeanUtil.toBean(shopJson, Shop.class);
        }
        if (shopJson != null){
            return null;
        }
        String lockKey = LOCK_SHOP_KEY + id;
        Shop shop = null;
        try {
            boolean isLock = tryLock(lockKey);
            if (!isLock) {
                Thread.sleep(50);
                return queryWithMutex(id);
            }

            shop = getById(id);
            Thread.sleep(200);
            if (shop == null) {
                stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY + id, "", CACHE_NULL_TTL, TimeUnit.MINUTES);
                return null;
            }
            stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY + id, JSONUtil.toJsonStr(shop), CACHE_SHOP_TTL, TimeUnit.MINUTES);
        }catch (InterruptedException e){
            throw new RuntimeException(e);
        }finally {
            unLock(lockKey);
        }
        return shop;
    }

    private static final ExecutorService CACHE_REBUILD_EXECUTOR = Executors.newFixedThreadPool(10);
    public Shop queryWithLogicalExpire(Long id) {
        String shopJson = stringRedisTemplate.opsForValue().get(CACHE_SHOP_KEY + id);
        if (StrUtil.isBlank(shopJson)) {
            return null;
        }
        RedisData redisData = JSONUtil.toBean(shopJson, RedisData.class);
        LocalDateTime expireTime = redisData.getExpireTime();
        JSONObject jsonObject = (JSONObject) redisData.getData();
        Shop shop = JSONUtil.toBean(jsonObject, Shop.class);
        if (expireTime.isAfter(LocalDateTime.now())) {
            return shop;
        }
//        缓存重建
        String lockKey = LOCK_SHOP_KEY + id;
        Boolean lock = tryLock(lockKey);
        if (lock) {
            CACHE_REBUILD_EXECUTOR.submit(() -> {
                try {
                    this.saveShop2Redis(id,20L);
                }catch (Exception e){
                    throw new RuntimeException(e);
                }finally {
                    unLock(lockKey);
                }
            });
        }
        return shop;
    }

}
